Air dielectric rotor for coaxial switch



May 31, I960 5. E. JACQUES 2,933,934

AIR DIELECTRIC ROTOR FOR COAXIAL SWITCH Filed Feb. 4, 1953 Q&

L1 5 nZU T George E. Jacques United States Patent 2,938,984 xn DIELECTRIC noronron COAXIAL swrrcn George E. Jacques, Independence, Ohio, assignor to Thompson Ramo Wooldridge Inc., a corporation of Ohio : Filed Feb. 4, 1958, sea-No. 113,151

1 Clainn (Cl. 100-153 V The present invention relates to a coaxial switch and more particularlyto one-employing a rotor having an air dielectric. I

" Coaxial switches, like coaxial lines, require suitable means to position and maintain the center conductor spaced from the concentric outer conductor and separated therefrom by a dielectric substance which will -trical characteristics suchas, a polytetrafluoroethylene resin ("Iefion)-with a low dielectric constant are not usually used since they are dimensionally unstable and are not usuallysuitable-for mechanically movingparts.

When, different dielectric substances are employed along the same coaxial line, each change in dielectric material results in an electrical discontinuity. One of theprincipal features and objects of the present invention is to. provide a coaxial switch having a coaxial .line po'rtion 'of novel structure.

" CA furtherobject of the present invention is to provide a novel coaxial switch having rugged and reliable mechanical characteristics and at the same time very good electrical characteristics.

A still further object of the, present invention is to provide a coaxial switch employing a novel rotor employing air as a dielectric and having the center conductor physically spaced from the outer conductor by spacers formed of a material having a low dielectric constant and low power loss such as polytetrailuoroethylene.

It is also an object of this invention to provide a novel and improved form of rotor assembly for coaxial switches.

It is still another object of this invention to provide an air dielectric rotor for a coaxial switch having a floating inner conductor within the rotor which is resiliently biased from one end.

'It is a further object of this invention to provide a coaxial switch which may be economically and simply produced.

Still another object of the present invention is to providev a new and improved coaxial switch having an air dielectric rotor mechanism permitting increased manufacturing and construction tolerances.

A still further object of the present invention is to provide an improved coaxial switch rotor having an air dielectric and a slidably movable center conductor.

Other and further important objects and features of the present invention will be apparent from the disclosures in the specification and in the accompanying drawings.

In the drawings:

Figure 1 is a cross-section of the rotor housing of a co axial switch;

Figure 2 is a sectional view of a coaxial switch rotor shown in Figure 1 but showing the center conductor in a slipped position within the rotor body;

Figure 3 is a fragmentary cross sectional view of the rotor center conductor mounting assembly as taken along the lines III--1H of Figure 2; and

'Figure 4 is a sectional view of a coaxial switch rotor employing a modified form of the present invention. There is illustrated in Figure 1 a preferred form of coaxial switch, indicated generally at 11 embodying the principles of the-present invention and readily adapted to be manipulated to interconnect desired channels by a rotor operator mechanism 12 coupled to the switch mechanism and arranged to incrementally rotate a rotor 13 forming a part of the switch mechanism. The switch 11, in Figure l, is illustratedin section to more clearly present the features of this embodiment of the present invention and the construction thereof. 'As the switch 11 is illustrated, it is provided with an end conductor connector 14 extending axially from the switch mechanism and a plurality of other channel conductor connectorslS and 16. Only two such other channel conductor connectors are illustrated in Figure l, but it should be understood that there may be any desired number of these radially extending, connectors such as the connectors 15 and 16. The number of other channel radially extending connectors is not critical to the present invention and is limited only by the dimensions desired for the switch and for the component parts thereof. The switch 11 has been illustrated with only two such other channel radially extending connectors for purposes of convenience.

An outer housing 17 having a plurality of radially extending pipe-like portions 18 and 19 and a similarly dimensioned axially extending pipe-like portion 20 is con- 'structed from a conductive material and forms the outer conductor of each of the connector assemblies 14, 15 and '16. The pipe-like portions 18, 19 and 20 are preferably axially 'hollow and are joined at a hub portion 21 which is :also hollow to provide an appropriate cavity for the rotor 13. Of course, the cavity in the hub 21 is joined with the hollows in each of the connector outer conductor portions 18, 19 and 20. It will be understood also that the unitary construction for the housing '17 is preferred but not essential and the housing 17 may be constructed from a plurality of appropriately machined or otherwise constructed parts fitted and secured together to provide the housing assembly with a construction resembling that illustrated and described here.

The rotor cavity in the hub 21 is preferably substantially cylindrical to accept the switch rotor 13 in rotatable bearing relation therein.

The rotor 13 is formed of a conductive material which is usually not the same material as the housing, but which may be of any other desired conductive material having desired electrical and mechanical characteristics. The rotor 13 includes a body portion 22 in the form of a segment of a cylinder and a pair of circular end flanges 23 and 24 (see Figure 2). 'The llanges 23 and 24 are formed to fit rotatably and bearingly within the cavity in the hub 21.

The conductor rotor block 25 forms the outer conductor coupling member for the switch rotor 13. The switch rotor assembly 13 is also provided with an inner conductor coupling member 26 which is concentric within a right angle passage or elbow 27 within the block 26. The conductor 26 is mounted on and supported by a pair of dielectric discs or spacers 28. The spacers 28 are firmly secured to and mounted on the arcuate center conductor 26 at slightly reduced portions thereof. The

J spacers are arranged however to slidably move within the hollow elbow passageway of the rotor blade 25. The spacers 28 are preferably formed of a material having good dielectric qualities such as polytetrafluoroethylene, commonly known as Teflon.

From the above description, it will be apparent that the coaxial line formed in the rotor assembly is essentially one having an air dielectric.

The axial. terminal 14 and the radial terminals 15 and 16 each have a pair of insulation members 29 and 30 which are centrally bored to receive and support center conductor members 31, 32 and 33 respectively. Each center conductor member has an intermediate flange 34 thereon and each is hollow at its outer extremity for connection to the line to which it is to be coupled. The inner ends of center conductors 32 and 33 are preferably solid and terminate in the surface of the central bore of the hub portion 21. The wall of the central bore, however, is provided with a concentric opening around .each terminal center conductor and of greater diameter to provide a suitable air-match section. Each insulator member 30 is cut back slightly at this same point to provide a shallow cut back of substantially the same diameter as the diameter of the opening through the Wall of the hub portion 21.

The center conductors 32 and 33 lie in the plane of rotation of the radially outer end of center conductor 26 of the rotor 13 and are arranged to electrically contact the latter when the rotor is turned to an appropriate position to align the same.

The center conductor 31 of terminal 14 is similar to conductors 32 and 33 with the exception that its inner end is also hollow and carries a spring-pressed plunger 35 which is constantly urged outwardly by a spring 36 against the end of center conductor 26 of the rotor 13. Since the center conductor 26 has a floating mounting, pressure of the plunger 35 against one end of conductor 26 necessarily presses the other end of conductor 26 against one of the conductors 32 or 33 or against the wall .of the recessed hub 21.

By the arrangement of Figure 1, it will be understood that when the rotor 13 is rotated by the actuator mechanism 12, the center conductor 26 will remain in constant positive coupling with conductor of the terminal 14 by the pressure of the plunger 35 caused by the spring 36.

Any wear on the abutting faces of conductors 26, 32, 33 and 35 will be compensated for automatically by the spring 36 since the whole assembly of the spacers 28 and the conductor 26 is free to slide within the block 25.

A modified form of the rotor assembly is shown in Figure 4 wherein the center conductor 26 is carried by three Teflon spacers 37, 38 and 39. Thus where additional support is required for the center conductor 31 three or more spacers may be employed, although the electrical characteristics and the floating mount is usually better with only two.

From the above description it will be apparent that a desirable air dielectric rotor construction has been provided without having large and objectionable discontinuities in the electrical characteristics. The construction is further rugged and reliable in use.

I claim as my invention:

In a coaxial switch, a housing including a cylindrical cavity, a plurality of coaxial line terminals supported in said housing each including outer and inner conductors, at least some of said terminals terminating at the cylindrical wall of said cavity, a rotor mounted for rotation in said cavity and having a toroidally shaped bore arranged to extend between a selected pair of said terminals, a curved conductor within said bore arranged to connect the inner conductors of said selected pair of terminals, said curved conductor having a plurality of reduced diameter recesses therein, an annular disc spacer of dielectric material disposed in each recess and having an inner diameter substantially equal to that of said recess and an outer diameter substantially equal to that of said bore, whereby said curved conductor together with said spacers are slidable into said bore in assembly, and spring means biasing the end of the inner conductor of one of said selected pair of terminalsinto engagement with one end of said curved conductor to urge the other end of said curved conductor toward engagement with the end of the inner conductor of the other of said pair of selected terminals.

References Cited in the file of this patent UNITED STATES PATENTS 2,426,186 Dow Aug. 26, 1947 2,747,059 Cockerham .May 22, 1956 2,766,355 Cherry Oct. 9, 1956 2,816,198 Cherry Dec. 10, 1957 

